Invasion of the Mutant Space Bats of Doom and the sequel Return of the Mutant Space Bats of Doom are two rare 'retro'-style shareware shooters.
From description at MobyGames: "[Invasion] consists of 66 stages, arranged in some sort of pattern (for example, every type of bats you encounter takes 3 stages to pass, each of three introducing new challenges). Once every several bats you kill you get one of four bonuses - purple gems, 6 of which grant you another life, a green gem which makes your missiles faster, a red one which gives you additional missiles per round, or a white gem which grants you a time-limited "hyper" mode.
[In the sequel,] the mutant space bats of doom return yet again to invade earth. Only you stand in their way of achieving their nefarious goals. As usual collect the different colored gems that can increase your ship's firepower, slow down the enemies, or add to the number of lives. In the bonus stage you turn into a bat and fly around collecting the maximum amount of gems to increase the chances of success in battle."
Both games are fun "old school" shooters that offer solid gameplay despite outdated graphics and cliche plot, as well as 'cute' enemies. Pop Software struck the right difficulty balance - the game is always challenging, but never frustrating. Neither of them matches the quality of the best shareware shooters (which must go to Raptor and Tyrian, no doubt), but they are fun enough to keep you occupied for minutes at a time. Worth a look.
After selling the game as shareware by mail-order in late 1990s, Pop Software resurfaced briefly in 2001 to sell both games via PayPal on-line, but they have disappeared again since 2002. Download the registered version below :)
Review By HOTUD
English 
Comments and reviews
Other Options (HARD MODE)
You can now add a "2" and/or a "n" to the command-line.
bats 2
The game is great but this version is not the full version, i just played and afther reaching level2 it says register the game to keep playing... so no full version here
This Game did could have remake?
I loved this game when I was a kid. I remember playing this when I was roughly 3-4 years old. I'm now 24 and can't wait to download and play this game. Such a nostalgic feeling.
fantastico juego DE MI INFANCIA!
This game is a classic, gorgeous!!!
Thank you very much.
It's an awesome game.
But when I reach with a boss the game crash S:
What can I do?
No comment nor review for this game at the moment.