Although co-op is very similar in many respects to the singleplayer (you play through a campaign, only this time with a buddy), there are a few crucial differences: first of all, a good co-op toolset has to be able to promote interaction between co-op partners to work properly. Although the Plasmids in BioShock can be used in tandem most of the time (such as when one player fires Electro Bolt continuously while the other melee rushes the enemy), at heart they're still made to be used alone. Therefore, the current Plasmid catalogue and its associated list of upgrades would need to change and expand to fit this. Secondly, the current Plasmid upgrade template, both within the game proper and in my own take, don't allow for much flexibility. Basically, my game would have the player be able to completely change their loadout in between levels, e.g. they'd be able to reset their Plasmid and weapon upgrades as well as choose which Gene Tonics they want to unlock.
Therefore, I propose a solution: rather than have every Plasmid expand on one single variation, each one will have three. That is, every Plasmid can be upgraded into one of three variants which, although they won't change the basic version, will grant it an extra function. Although you can't use two variants of the same Plasmid at once, you can unlock several of them (in any order) and switch between them at a Gene Bank. In addition, the base version and each variant can be enhanced with up to three independent upgrades. This means that you have complete freedom over how you want to tailor your Plasmid: you could either upgrade your Plasmid to a specific version and upgrade said iteration, stick to the base version and upgrade it, or do both at the same time to maximize its power. In addition, each upgrade would be relatively cheap: upgrading a single Plasmid to one of its three variants and then purchasing all six available upgrades (three for the base version, three for the added ability) would cost as much as upgrading a Plasmid to level three in the singleplayer, so you'd have more room to test new powers.
Boring technical jabber alert: Again, since this upgrade system differs completely from the one in the BioShock series, the Gatherer's Garden interface would have to change accordingly, otherwise it would overflow with Plasmid upgrades and sub-upgrades. Like in my singleplayer version, the GG would list every Plasmid but not their upgrades, and clicking on them would show their own upgrade trees. In this case, it wouldn't be so much an upgrade tree as an upgrade... solar system, or something like that. Around the main Plasmid its three variants would be arranged around it, and then each version's three mini-upgrades would sit around their own respective iteration (including the base version).
Also, all changes I'd like to make to the baseline effects of each Plasmid can be viewed in their respective articles listed in the Singleplayer Plasmids section.
List of Plasmids[]
- Electro Bolt
- Incinerate!
- Winter Blast
- Hypnotize
- Decoy
- Security Command
- Cyclone Trap
- Insect Swarm
- Telekinesis
- Scout
- NEW!: Chrono Warp
- NEW!: Teleport
- Gravity Well
- NEW!: Buddy Boost
- NEW!: Presto
Credit goes to Androyd09 for finding the first and second secret Plasmids, Buddy Boost and Presto.