It's either really boring or really irritating depending on how well you do at the start. Some annoyance (no pause, no map, no status, no autofire) are fixed by bubble tanks 2, but the game is still just as boring and endlessly samey.
It's really not that original you know. There's only this little known shooter called Einhander that lets you do exactly the same thing just in a more clear fashion. Not bad though, but the keyboard is a significant disadvantage compared to the mouse.