Looks fun.
1. The opponent, being non-idiotic, will not purposefully try to kill it. So you'll have to do the job.
2. Recluses form a duo, like Unstable Gas itself. However, Recluses have low HP (2 to 3) and therefore can't trigger Blimp/Zeppelin many times. Also, while UG can be paid off the mark, Blimp/Zeppelin can't. Besides, 10 damage once for 5 quanta requiring a duo is kinda pathetic compared to Elite Wyrm and Pegasus.
3. The only really effective way to kill it, other than Web, is Gravity Pull. You save yourself from 10 or more damage and deal 10 damage to the enemy, requiring a duo with one element (
) paid off the mark. In this way, it's on par with UG... but UG is only one card, while this is two (GP + Blimp/Zeppelin).
From 1, 2 and 3, I conclude in the absence of UG on the field, this card is massively UP.
With UG on the field, they detonate, allowing you to play and use UG without including a source of
. However, to do this you need Blimp, which requires a source of
,
, or
. So you haven't gained much advantage with this. So even with UG being triggered, it's still UP.
Edit: Forgot Immolation/Cremation.