The original Slayin was a mobile marvel of simplicity; a lovely little bite-sized twitchy RPG-ish thing where you effectively just moved left and right putting holes in enemies and using their dropped loot to improve your stuff. It was a familiar rogue-lite approach that worked brilliantly for a few rounds at the bus stop. In moving the sequel to Switch, developer Pixel Licker has sensibly overhauled the progression into a more traditional and satisfying "Story" mode, while retaining the same addicting gameplay flow and incremental upgrades.

Taking place on single-screen levels across two "planes" (not unlike the Saturn classic Guardian Heroes), Slayin 2 boils combat down to five buttons – left, right, jump, switch lanes and attack. That last one is a bit of a doozy, though – in Slayin 2, simply moving left and right has your hero raise their weapon, and touching enemies in this state will damage or kill them. For the fodder monsters such as your traditional "slime", this means the earliest stages are spent simply walking back and forth, hopping between lanes to mop up enemies as the omnipresent timer counts down. And that's really the crux of Slayin 2's gameplay – you kill enemies, mostly by walking into them, and when time runs out you fight a boss. It's difficult to make it sound interesting, but it's everything layered on these simple mechanics that make it work.

The aforementioned attack button lets you use a "spark" – a special attack that you gain limited uses of by attacking enemies normally. Killing enemies with your "spark" drops better, higher-value loot, which directly translates to more money to spend on weapon upgrades, recruiting new warriors and restoring the townships that have been razed to the ground by the hostile creatures you're striking back at. Sustained slaying without taking damage also increases your loot multiplier, and it's easier said than done due to a wide variety of different monster types, some with multiple attacks.

It's the variety and ensuing carnage that elevates Slayin 2 – Flying enemies! Enemies with polearms that can only be hit from behind! Enemies that throw projectiles between lanes! Enemies that poison you! It's constantly engaging, forcing you to focus and study the battlefield to find the best path not only to gather maximum coinage, but simply to stay alive.

The graphics are as good as they need to be, with attractive pixel art that doesn't fall into the generic, flat look of so many throwbacks. Occasionally you'll face a boss that looks like it has fallen out of a different game, but mostly there's a pleasing consistency to it all and you won't find yourself confused or unable to discern an enemy or its weapon in the heat of battle.

It's fun to explore the map and see what new twist the developers have cooked up next. With each level being not much longer than a minute or two, the game is easy to pick up and play, with even a failed stage yielding coins; you're never too far from the next new thing, which keeps things compulsive, but there is a grind involved to some extent to level up every weapon for every character.

For fans of the original Slayin, a more familiar "Arcade" mode that eschews any kind of narrative is present, and full local co-op in either major mode is a welcome bonus. Overall it's a package we think is well worth the asking price, something that's brilliantly simple in principle, but reveals its intricacies and hidden difficulty as you play through; it wouldn't be entirely out of place in a late eighties arcade.