Red moves at 5 and has a turn radius of 3, Blue moves at 8 and has a turn radius of whatever it takes to get to Red's location. Nitro gives Red +8 while holding 'x', but Blue is always going to catch Red with the turning handicap. If anything it should be vice verse with the turning, that way the lack of speed on Reds part can be made up by out maneuvering Blue.

From what I see it's Up Down Left Right ... but the chase car (blue) is faster and the hit box of the player car (red) is way to big. You lose without even being touched. Graphically anyways.

Like the concept, but you need to make the Square move via keyboard commands or follow the mouse. Preferably keyboard commands. Not being able to attack and move at the same time takes a lot away from the game. Also, a graphical representation of the shield would be a nice addition to see.

This is just off the top of my head, but I'd think implementing a timer then setting each bug type to only spawn so many within so many seconds. To keep it interesting, I'd try to have that number increase with the total amount of time that has passed in the game or make it relative to the total number of bugs the player has spawned into the world. For example: Ant can only spawn 5 every 3 seconds. Lady Bug can only spawn 1 every 5 seconds. Special Bug can only spawn 1 every 60 seconds, but only after 20 Lady Bugs have spawned. Butterfly can only spawn 3 every 60 seconds, but only after 50 Ants have spawned. Then every 120 seconds (or whatever) increase how many can spawn within those time frames.

Playing this game, and some of your 3D games, proves to me I made the right choice in learning Java with Greenfoot! Your work is amazing and I can't wait to see more.