If engulf works like Devour and only can target creatures with less hp you need to make note of it in the notes section at the very least.
"Original Creature" or "Original Stats" refers to the stats that would be shown on the card while it is in your hand. You probably meant "Current HP" which refers to the hp as it currently exists including both temporary and permanent modifications to that instance of the creature type.
Additionally this card is more complex than it needs to be. I count 4 separate cards (Engulf, Split, atk=hp/2 and gain +0|1 per turn) inside this one.
Suggestion: Drop the Engulf and Atk=hp/2 abilities and change the card text to:
"Split: Slime splits into 2 Slimes with half the current stats.
Slime gains +0|1 per turn."
This way it is simpler (another of Zanz's comments) and it can fit all the card text on the card image.
Zanz decreed upon witnessing the problems the
first Alfatoxin had caused that there would be no more instant kill cards that did not take the hp of the target into account. Flooding and the Freeze + Shockwave combo are the only instant kill card that ignore the hp of the target that has not been preemptively vetoed.