tohya.net
Tiger-Heli is one of the earliest vertically scrolling shooting games, if not the first. For a game that was released in the same year as Gradius there is a surprising lack of technical issues. Everything in Tiger-Heli just works. The hit boxes are just right, power up items don't get stuck anywhere or vanish into oblivion and the framerate stays at an acceptable rate throughout. There's only a couple of tracks in Tiger-Heli, but all of them sound really good. The visuals are also not too bad: while the backgrounds are very simple the sprites have good detail for their time. Only the mechanics of this game give away its age.
The player heli's shot range is limited to less than half the vertical screen size. There are no direct shot upgrades. Instead upgrades add Little Heli's that attach like fixed options to the sides of the main heli. These have their own hitbox and get taken out when hit. Given the massive size of the total hitbox with options, not losing them is a challenge in and of itself. Tiger-Heli already features bullet cancelling bombs, but limits them to two. They're also attached to the player sprite and explode on impact with enemy bullets, making this the earliest game with auto bombs. Flying close to enemies does not prevent them from shooting, making for a unique experience coupled with the player's limited shot range. The game almost feels like a dance as you weave back and forth to hit enemies and dodge their fire.
I didn't have high expectations going into this one, but Tiger-Heli turned out to be surprisingly fun. Although its mechanics may feel outdated and take some getting used to, this is actually a solid game in its own right that one can have a good time with even today.