The Sky Force series began on mobile before moving on to more traditional games machines, with Sky Force Anniversary arriving on a number of systems (including the Wii U) not so long ago. Now it comes to Switch, providing its blend of fun and grinding as you blast through a number of levels, replaying them many times over to meet the requirements to earn medals and collect stars (the in-game currency) to purchase upgrades for your ship. If this sounds familiar, then that’s because the follow-up, Sky Force Reloaded has already been released on Switch and consequently while Sky Force Anniversary offers similar shooting thrills to Reloaded, it feels like a step down in some areas.

For starters, you have just the one ship, whereas Reloaded had multiple options (assuming you collected the parts). Similarly, technicians who could provide buffs to your ship are absent in this instalment. You do have the same upgrade options, however, allowing you to add permanent additions like missiles, side-cannons and a magnet (to attract stars) to your craft as well as the ability for the limited use items: shields, bombs and powerful laser blasts. Reloaded featured thirteen (and three bonus) levels compared to the nine offered here and had a larger variety of enemy types to deal with. It had better bosses, too, as with a couple of exceptions, Sky Force Anniversary’s are not as memorable.

But though Sky Force Anniversary offers a bit less, it still provides enjoyable shooting action, packaged up in the same audio-visual style. The 3D graphics provide a good amount of detail and depth to the stages, while keeping the action easy to follow - although sometimes it can be difficult to tell if that missile that's circling around the screen is from an enemy or if it's one of your own. A variety of trees, rocks, seas, desert and factory-like areas feature in the stages, although some end up looking quite similar. Overall there’s a bit less scenic variety than in Reloaded and less flair, whether that’s a fleeing speedboat looking a bit simple compared to a fleeing buggy or relatively calm water compared to choppy seas.

There are some (admittedly rare) moments where performance dips but overall things run smoothly and the stages could be slotted into the other game without seeming out of place. Synth music again backs the onscreen action, providing a good combination of adventurous tracks and is enhanced by the punchy sound effects. There’s a good range of explosions, whirling, rockets firing, beeps and voiced soundbites for the likes of “Weapon Upgrade”, “Health Restored” and commentary on your chain of kills ranging from “Nice” to “God-Like”.

Moving at a fairly relaxed pace, the gameplay nevertheless involves a lot of weaving around the screen with bullets, missiles or just enemy craft coming at you from multiple directions and at differing speeds. Nothing moves too fast, but if you don’t take out your attackers quickly you'll find the density of attacks dramatically reduces your free space, making safe passage tricky and leading to hits to your health or even complete destruction. Speaking of foes, there's a good range of enemy craft on offer here. Some small ones fly in groups, twisting and turning, and it can be tough to hit them all, while larger ones move slower but fire at you with bullets and/or missiles. The likes of static turrets and cannons provide further trouble, giving you a number of things to have to deal with on missions.

How you approach the expanding challenge thrown up by the game is up to you. Do you go for increased health or ignore that in favour of powering-up your weapons? Do you try and level-up things equally or initially focus on your magnet to make grinding for stars for the other upgrades easier? Whatever approach you take, you will be replaying the levels multiple times. Not necessarily because you lack sufficient upgrades to see you through, but because (like Reloaded) clearing one stage is not the only requirement to get to the next; you also need to have collected a set number of medals.

As before, medals are typically awarded for destroying 70 percent and 100 percent of the enemies, clearing the stage without being hit and rescuing all the stranded people (hover over them for a moment to collect). You can try and achieve all of this in one go (and it’ll certainly help your score), but it’s easier if you don’t. You’re going to be replaying the levels anyway so you might as well mix things up, with rescue runs, total destruction and self-preservation flights providing a different feel to each of the others.

Stage five is this game’s 'no weapon' level, swapping out the enemy destruction goals for star collection ones. With an EMP blast taking out your armaments at the beginning of the stage, a steady hand is required to slip between the slow but constant lines of bullets and occasional cannon fire. Or, if you’d like to play a bit differently, it is possible to dodge the EMP blast. This doesn’t turn it into a regular level however as the blast continues to chase you throughout, requiring fast reflexes as you attempt to snake away from it while hoping to destroy the various turrets and bullet-spewing machines before you plough into them. Either way of playing the level provides a change of pace to the rest of the main game that works well, but it is the frantic movement of the EMP avoidance approach that provides the most fun.

Another weaponless experience is provided by the game’s Weekend Tournament mode, although here, rather than engineer a reason for your lack of firepower, your offensive capabilities are simply disabled. The stage is a short but looping one with stars to collect and people to rescue as you slide between the enemy fire. Typically, the longer you survive, the better your score. It’s the kind of mode that would benefit from a global leaderboard, but as that’s not included it doesn't offer much in the way of long-term appeal.

The main game does offer plenty of replayability, however, as further difficulties can be unlocked on stages once you’ve acquired all four medals. This provides an entertaining increased challenge, but can also be useful if you need medals to unlock the next stage as you can go back to one you’ve got good at to collect more; the 70 percent mark is usually achieved without trying if you simply clear the level. Replaying levels to achieve more goals, collect more stars and generally destroy extra stuff allows for an increased score and this too adds to the fun as you find ways to bump up your score.

Conclusion

You have to grind for upgrades and replay stages to ensure you've met the requirements to unlock the next, but Sky Force Anniversary keeps the action entertaining. Trying to acquire each of the medals on playthroughs feels different enough to prevent things from getting too repetitive, and there's always the challenge of trying to get them all in one go. If you want to test your skills then the additional difficulties that can be unlocked will scratch that itch, and there's also replayability in trying to improve your score. As enjoyable as this is, it's something that has already been done - and done well - by Sky Force Reloaded. But if you've already played through that and are looking for more, then Sky Force Anniversary provides another batch of missions to sink your teeth into - albeit with a few less bells and whistles.