You can run in the original (classic?) CyberVirus game too. In fact, I highly recommend it on at least one mission when 10+ robots start chasing you down right away. Strafe was a new feature I added to CyberVirus.
Back on topic: yeah, the spider can be deadly and so can the centipedes when they get faster! The spider intentionally appears infrequently on the first few levels, but then becomes more frequent as the game progresses; that's another tweak I added to the game. I'm a sucker for classic arcade games as it is, but I really had fun fine-tuning this game and still enjoy playing it now. Thanks to @LordKraken who suggested I add the level indicator and save, so you can compete both for score and for level!
How do you like the music? Again, I wanted to give it that full-featured arcade feel, so I added three songs: title song, GAME OVER song (very short), and high score song. This was using a custom music player I wrote to keep it lean and easy to squeeze in RAM with the existing game. I'm using the same music engine but with improvements in Microvaders.