A trio of indie developers are putting unusual spins on Serious Sam in three downloadable games to promote, publisher Devolver Digital has announced. As marketing campaigns go--and we presume this is all part of the one for Croteam's Serious Sam 3--The Serious Sam Indie Series certainly is interesting.

Serious Sam: Double D is described as "a frantic side-scrolling shooter" with "killer hand-drawn artwork" and an "innovative weapon stacking system." Made by Explosionade developer Mommy's Best Games, it'll hit PC and consoles.

Mobile title Serious Sam: Kamikaze Attack! is an "auto runner"--think Canabalt--starring bomb-headed Kamikazes. Be-Rad Entertainment, developer of Lame Castle, is behind it.

Lastly, but by no means least-weirdly, Serious Sam: The Random Encounter is a turn-based RPG from Vlambeer, maker of Super Crate Box. "Arm your squad to the teeth with massive ordinance, throw down some special items and take aim at the hordes of charging enemies holding that sweet, sweet loot you crave so badly," reads the description.

"Croteam has always been proud to be an independent studio working on something that we created ourselves and truly love making each game," said Croteam CEO Roman Ribaric in the announcement. "We wanted to put our beloved Serious Sam in the hands of some of today's best indie developers out there and see what they would come up with. I think Serious Sam fans and fans of these brilliant developers will be really happy with the great games they're developing now."

The three games will be released "over the coming months" ahead of Serious Sam 3's launch this summer. Serious Sam: Double D and Serious Sam: Kamikaze Attack! will also be playable at PAX East.