You wrote it made 13th place in the F3 league, did you mean the F2 league ? I'm guessing that's what you ment since the previous version got further in F3 and since it's no longer allowed in F3 since it uses shell.
And gratz, you're over half way through F2
And you can push this a lot further, so far you're only using shell, with venom and poison it'll be even stronger.
I would sugest taking a look at the F3 bot called Defence and see what seperates it from the previous bot. It has a gene for shooting back when you get hit... if you used that gene with some venom maybe then if your bot is eating an alge or enemy and something else attacks it from behind, then you can spend a venom shot on the agressor from behind and go back to what you where doing. This can be very effective, you can find the same gene in Multiply4, it's very potent, especialy with the setup from Multiply4 (It uses venom to cause -2 shots and uses a large dose of venom, so it can fight many oponents at the time while all of them are feeding it, it a very usefull litle gene).