Playtesting...

 I have tried playtesting, it is fun, unless you are stupid and your game sucks. Then it is not. 

Some notes on online playtesting: 

Printing out the notes you have helps a lot. While electronic documents are easy to edit and have search options, when you have a printed out page, you can see it all. It helps to find stuff that you want to find. 

Having a blank piece of paper helps. I never have one when I play. I make notes and draw maps on the other side of my printouts, character sheets, uncut paper minis, and that's suboptimal. 

When making a map it's a good idea to keep one sheet for a map and the other for notes. While it's good to write stuff on the map when you're making a module, when you're actually playing, it's more convenient to put a number or a symbol on the map and write the note on a different sheet, rather than make your corridor squirm around the "GIANT SPIDER HERE!" text. 

My attention span is short. After three hours of playing I start cutting out paper minis in worrysome quantities. 

Also, cutting off a head of the paper mini that looks like the monster you've just killed is amusing for the party.  

We crawled through a Nebulith (soon to come Okinawa-themed LotFP-compatible book) adventure. The new character classes are seriously cool. I liked how the professions worked in Usagi Yojimbo game, and these are doing a similar thing, only better. 

And it's always nice to meet an NPC that you know and like. 

P. S. 

"So the floor is lava?" 

"Yes". 

One combat round later: everyone is in lava. 

Two combat rounds later: everyone checks if you can swim in lava.