Hi, thank you for your time and for your thoughtful review.
Yes, the combat system is complex for a jam game, if this becomes a real game I'll probably have to let the player learn at a slower pace. In the end this is the logic: each card has an effect and a condition for the sequence to continue, meaning to pass to the next card.
Yes, the starting pool is random, the player is supposed to think about his unit's stats and available starting cards. Concerning teleport, generally units that have that free card also have high HP, so you can use teleport to move them to choke points and use them as shields in the early levels. Units can target themselves or their allies because it can be useful in many occasions, for example to trigger the shield of one your allies or to trigger a damage-reacting card. You can also heal enemy units, which can be useful in some situations...
Again, thank you very much for your feedback, I'll soon play your game too :)