Though the DSi has no native motion-sensing capabilities, it hasn't stopped developers from trying to use the system's built-in cameras to approximate the tilt-sensors of the iPhone. As expected however, cameras are not motion sensors and although the latest effort from Genki Mobile includes a fair collection of mini-games involving flying and shooting targets, it all ends up feeling more like an extended tech demo than something fun to play.
Unlike another game we recently previewed, Geki Tsui Ō doesn't appear to use any head-tracking. Instead prior to any game start your biplane will be displayed during a calibration process that requires you to be still for several seconds as the camera apparently marks a horizon against which it will adjust the on-screen action. If you tilt your DSi during calibration the process will not complete and since the position is the "zero level" during the game, you'll want to make sure you're holding your DSi comfortably while it does its thing. Unfortunately, unlike Rittai Kakushie Attakoreda, the calibration process will complete even if it doesn't result in a playable experience, meaning you could end up with an unplayable game; as with Nintendo's camera-controlled game, the same bright ambient lighting requirements exist here.
Assuming you're in a brightly lit room, however, you'll find that the use of cameras for motion-like input does a decent job, though there is a noticeable delay between tilting the DSi and your plane banking. The pacing overall is rather slow making dogfighting more akin to duelling airships than one-seat fighter craft and you certainly won't be pulling off stunts like barrel rolls or loops - not that we would expect too much of these in the WWI-era craft you're piloting. There are three main game modes: a training mode where you can just fly around and pop balloons, multiplayer (requires separate downloads for all your friends, so unless you've all got Japanese DSis you're out of luck) and a single-player mission mode with four games to play.
Single player games are all essentially target shooting: shoot as many balloons as you can in a fixed time period, shoot balloons in order by the numbers printed on them, avoid balloons and run into stars to collect as many as you can and lastly, shooting other planes. Whilst the last entry may not sound like target shooting the fact that the other planes rarely go after you and instead will shoot at you if you happen to cross their path (sometimes) makes it pretty much the same as the other games except that the planes travel about rather than hanging in the air waiting for you.
Visually, it's pretty impressive for a 3D DSiWare title, though you will see a lot of pop-up; with the camera in chase mode behind your plane it's not always easy to tell how far you are from your target even with a radar display in the lower screen. Tilting your DSi adjusts the roll and pitch of the aircraft and you can use a button to engage turbo to pull off sharper turns for doubling back to get that balloon or plane you just missed, though we noted that rapid adjusting of your DSi's angle can confuse the camera-based sensors, resulting in opposite input being detected or a lack of any response at all; clearly illustrating the limitations of this technique.
We'd imagine if you did have a passle of friends this could be fun in multiplayer, but the glacial pacing would probably wear away the novelty of the experience before long. Truly this is a game that would be better on a system using actual motion detection which would have enabled more focus on the gameplay and provided a more satisfying experience. As it stands it's a 500 Point tech demo that's unlikely to get much play time given the restrictive conditions under which it can be played and the overall quality of the experience.