Small improvements and bugfix from players input — HellEscape Steam update #814179

Minor fixes from players feedback - Fixed the flickering in the powerups menu. - Made the wanderer slower when you fall behind + added clearer visual indicator of danger when you stray too far. - Added an option to refund powerups in exchange of gems. - Added 500 gold compensation if player finds an artifact they already own. If you requested something and I didn't reply at all or said I'll do it and its not here - please give me a reminder! Thanks :)